Geology 2C Exam 2 Practice Test (answer key at bottom)
Professor Bennington

Test yourself before the real exam! If you are not sure of an answer I suggest that you try to find it in your notes or in the textbook. If you just look it up in the key you will not learn very much.

Note: This practice exam includes a few questions on the Proterozoic. Don't panic.

1: The most primitive organisms found on the Earth today are members of which group?
1: fungi
2: plants
3: archaea
4: eucaryotes
5: protoctistans

2: An orogeny is best defined as:
1: a Roman party
2: an episode of mountain range formation
3: a type of volcanic eruption
4: an episode of magma movement in the mantle
5: a type of plate boundary

3: The first direct fossil evidence for life on Earth is found in which Eon?
1: the Hadean
2: the Archean
3: the Proterozoic
4: the Phanerozoic

4: The relative positions of continents in the past can be determined in part using which lines of
evidence?
1: the position of ancient mountain ranges.
2: the degree of similarity in fossil species between two places.
3: the distribution of climate indicators such as coral reefs, coal beds, and evaporite
deposits.
4: all of the above
5: both 1 and 2, but not 3

5: Even though the Sun was dimmer in the Hadean, the Earth did not freeze for this reason:
1: The Earth was closer to the Sun.
2: The Earth had more internal heat.
3: The Earth had more carbon dioxide in its atmosphere.
4: The Earth had more nitrogen in its atmosphere.
5: The Earth did freeze in the Hadean.

6: Which event in the history of life probably occurred near the middle of the Proterozoic?
1: the origin of life
2: evolution of first cyanobacteria
3: evolution of first eucaryotic protoctistans
4: evolution of first animals with shells
5: evolution of first vertebrates

7: This kingdom includes single-celled organisms with complex organelles such as chloroplasts and mitochondria.
1: Kingdom Protoctista
2: Kingdom Bacteria
3: Kingdom Fungi
4: Kingdom Animalia
5: Kingdom Plantae

8: What was the source of rising oxygen levels in the Archean atmosphere?
1: comets
2: electrolysis of H2O by lightening
3: photosynthesis by cyanobacteria
4: chemical weathering of iron oxides
5: volcanic outgassing

9: Archaea are good candidates for the first organisms because of these characteristics:
1: they are very simple in their physiology.
2: they are hyperthermophiles.
3: they are chemautotrophs
4: all of the above
5: none of the above

10: Direct evidence for glaciations occurring in the Proterozoic comes from what source?
1: widespread tillites from the Proterozoic found on several continents
2: estimates of ancient levels of atmospheric carbon dioxide
3: estimates of ancient sea water temperatures
4: the abundance of stromatolites found in Proterozoic rocks
5: ancient glacial ice preserved on several continents

11: Archean sediments appear to have been mostly deposited where?
1: on land.
2: on broad continental shelves.
3: along the margins of island arcs
4: in rivers
5: in shallow lagoons

12: What is the name given to a widespread, but difficult to interpret, group of fossils in the late Proterozoic that consist of the impressions of soft-bodied animals in sandstones?
1: the Proterozoia
2: the Ediacaran fauna
3: the terminal Proterozoic fauna
4: the dawn fauna
5: the Impressionozoa

13: Conclusive evidence for the evolution of the first multicellular animals is found when?
1: the late Archean
2: the early Proterozoic
3: the late Proterozoic
4: the early Phanerozoic
5: the late Phanerozoic

14: Flesh, muscle, and other types of soft tissue usually do not fossilize because...
1: they decay rapidly.
2: they are not mineralized.
3: they are not usually buried.
4: they are not organic.
5: both 1 and 2.

15: The first evidence for the formation of large continents with extensive shelf areas is seen in rocks from which eon?
1: the Hadean
2: the Archean
3: the Proterozoic
4: the Phanerozoic

16: Mound-like sedimentary structures formed as cyanobacteria grow into mud-trapping mats are called:
1: stromatolites
2: stromatoporoids
3: stromatactis
4: mounds-o-mud
5: mud-mounds

17: Why is hybridization usually discouraged by natural selection?
1: hybrids are always sterile
2: hybrid offspring are always sterile
3: hybrids are often less well adapted than purebreeds
4: hybrids are often better adapted than purebreeds
5: hybrids are less energetic than purebreeds

18: Which of the following is a reasonable statement defining sexual selection (SS)?
1: SS occurs only when females choose mates
2: SS occurs only when males choose mates
3: SS is fundamentally different from natural selection
4: SS is an extension of natural selection through mate choice
5: SS is counteracted by natural selection

19: The supercontinent of Rodinia is believed to have assembled from plate collisions during which time?
1: early Archean
2: Late Archean
3: early Proterozoic
4: late Proterozoic
5: Cambrian

20: The beginning of the Proterozoic Eon is marked by which event?
1: the origin of life
2: the formation of the atmosphere
3: the assembly of the Rodinia supercontinent
4: the formation of large amounts of continental crust
5: all of the above

21: A possible explanation for the "Cambrian Explosion" is:
1: a change in ocean chemistry made it energetically easy to secrete shell mineral
2: the evolution of predators forced prey to evolve protective coverings
3: oxygen levels in the atmosphere reached a critical level, giving organisms more energy to make shells
4: explosive release of methane gas from the seafloor
5: 1, 2, and 3 are all possible explanations

22: The Archean Eon begins with this event:
1: the formation of the Earth's oceans.
2: the formation of the Earth's atmosphere.
3: the formation of the Earth's crust.
4: the formation of the oldest rocks preserved on the Earth.
5: the formation of the solar system.

23: Magnetic reversals describe this phenomenon:
1: the reorientation of a rock within a magnetic field
2: the loss of the remnant magnetism from a rock with heating.
3: the change in mineral composition of a rock due to magnetism.
4: the periodic reversal of the polarity of the Earth's magnetic field.
5: all of the above.

24: Which of the following is evidence for an ancient continental collision?
1: Large regions of basaltic lava flows
2: Large regions of metamorphic rock
3: Thick sequences of carbonate sedimentary rock
4: Normal faults
5: all of the above

25: What is a banded iron formation?
1: A rock consisting of alternating thin layers of iron oxide and chert.
2: A rock formation characteristic of the Archean.
3: A rock formation characteristic of the early Phanerozoic.
4: both 1 and 2
5: both 1 and 3

26: Carbon in rocks that is enriched in the isotope C12 is evidence for?
1: High levels of carbon dioxide in the atmosphere.
2: Plate tectonic collisions.
3: Low levels of oxygen in the atmosphere.
4: Metabolic activities of organisms.
5: Meteorite bombardment.

27: During a regression, what happens to the shoreline?
1: it moves seaward
2: it moves landward
3: it remains in the same place

28: Which team of scientists proved that organic molecules can be formed abiotically?
1: Watson and Crick
2: Penn and Teller
3: Urey and Miller
4: Raup and Stanley
5: Curie and Curie

29: 1.0 Ga metamorphic rocks buried beneath the eastern margin of North America are evidence for which geologic event?
1: collision and occurrence of the Grenville Orogeny
2: rifting of the Rodinia supercontinent
3: formation of the Rodinia supercontinent
4: both 1 and 3
5: both 1 and 2

30: Plate tectonics in the Hadean would have been different than today in which ways?
1: larger plates in the Hadean, slower seafloor spreading
2: smaller plates in the Hadean, more rapid seafloor spreading
3: fewer volcanoes in the Hadean
4: larger plates in the Hadean, more rapid seafloor spreading
5: smaller plates in the Hadean, slower seafloor spreading

31: Detrital pyrite and uraninite in Archean conglomerates is evidence for what?
1: Low levels of oxygen in the atmosphere.
2: High levels of oxygen in the atmosphere.
3: High levels of carbon dioxide in the atmosphere.
4: High levels of methane in the atmosphere.
5: Formation of large continents.

32: The Great Unconformity above the Vishnu Schist at the bottom of the Grand Canyon is evidence for what event?
1: plate collision and mountain building in the western US near the end of the Proterozoic.
2: rifting and plate separation in the western US during the Cambrian.
3: development of a passive margin in the western US in the late Proterozoic
4: rifting and plate separation in the eastern US during the Cambrian.
5: transgression during the late Proterozoic

33: The Earth is about 4.6 Ga old. The Ga stands for?
1: Gazillion annum
2: Giga annum
3: General age
4: Gobs ago
5: Gazillion ago

34: Presently, the eastern coast of North America is best described as?
1: A rifting continental margin.
2: A colliding continental margin.
3: A passive continental margin.
4: A subduction zone.
5: A transform fault.

35: Icehouse conditions in the Proterozoic did not become permanent because...
1: volcanoes added new carbon dioxide to the atmosphere
2: cold conditions prevented the formation of new limestone
3: the sun increased in brightness
4: both 1 and 2
5: both 1 and 3

36: The evolution of eucaryotic protoctistans probably occurred when?
1: during the Hadean
2: during the Archean
3: during the Proterozoic
4: during the Phanerozoic

37: The presence of 4.2 Ga zircon grains in the oldest metamorphic rocks is significant for which reason?
1: It shows that the oldest metamorphic rocks are 4.2 Ga in age.
2: It shows that the Earth formed at 4.2 Ga.
3: It shows that meteorites were impacting the Earth at 4.2 Ga.
4: It shows that the Earth was still homogeneous at 4.2 Ga.
5: It shows that some continental (felsic) crust must have formed by 4.2 Ga.

38: Which of the following did NOT occur during the Hadean Eon?
1: accretion of the Earth
2: formation of the oceans
3: outgassing of the atmosphere
4: formation of large continents
5: initiation of plate tectonics

39: A relative fall in sea level is called a...
1: transgression
2: regression
3: intergression
4: agression
5: progression

40: Chert deposits in the Archean Warrawoona Group of Australia and the Fig Tree Group of South Africa are famous because they contain:
1: deposits of gold and platinum
2: the oldest possible evidence for fossilized cells
3: the oldest possible evidence for animal life
4: the oldest evidence for atmospheric oxygen
5: the oldest evidence for volcanic activity

Answer Key

1 3

2 2

3 2

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6 3

7 1

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9 4

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11 3

12 2

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14 5

15 3

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27 1

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39 2

40 2